Mass Effect's Interactive Comic walkthrough •
Page 12

You decide to destroy a base containing vital research that includes a cure for the Genophage - a genetically engineered disease designed to stop the Krogan taking over the galaxy. Wrex, your Krogan ally disagrees violently. With Wrex at your mercy, you feel you have no option but to terminate him.

Mass Effect Comic: Decision 3, Kill Wrex

"Before I could convince him to stop... he ran, leaving me just second to extract my squadmates. I tried... but I wasn't fast enough. I could only save one of them."